What is the correct way of forcing maven to use HTTPS for maven central?

You don't have to place it into all POMs one by one. I'd rather suggest to add the following code into MAVEN_HOME\conf\settings.xml into <profiles> section:

<profile>
    <id>maven-https</id>
    <activation>
        <activeByDefault>true</activeByDefault>
    </activation>
    <repositories>
        <repository>
            <id>central</id>
            <url>https://repo1.maven.org/maven2</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>central</id>
            <url>https://repo1.maven.org/maven2</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </pluginRepository>
    </pluginRepositories> 
</profile>

This will be always an active setting unless you disbale/override it in your POM when needed.

This is already fixed in latest maven 3.2.3! See the changelogs!

So install maven 3.2.3 and do 'rm -rf ~/.m2/repository/*' for a better feeling ;)